In general, patients suffer from indigestion due to impaired function of the stomach and intestine, so that sufficient nutrition cannot be ensured with food alone. Thus, Ringers solution contained in a Ringer-pack is injected into a blood vessel of the patient to provide necessary nutrients, in particular, glucose, to the patient.
For oral medication, various products have been developed, which can maintain effects over 24 hours or more, but, in the case of injectable medicines, it is difficult to maintain effects for 24 hours. However, it is well known that, if the injectable medicine of a predetermined amount or more can be continuously administered at a constant rate for 24 hours or more, the injectable medicine can provide more constant effects than oral medication without side reactions.
In particular, for infants, an administration amount of a liquid medicine is determined in proportion to a weight of the infant patient (in other words, an injection amount of the liquid medicine is determined by multiplying an injection volume of the medicine per kg by the weight of the infant patient), and thus it is necessary to provide a device which can deliver the liquid medicine for a predetermined period of time through flexible adjustment in the injection amount of the liquid medicine.
Additionally, since infants frequently move about during administration, there is a problem in that, when the liquid medicine is administered using a conventional clamp, the clamp becomes loose due to movement of the infant patient, making it difficult to inject the liquid medicine in an exact amount.
Furthermore, when administrating a special liquid medicine for injection, such as anti-cancer agents, antibiotics and the like, to a patient in critical condition, the liquid medicine must be continuously administered at a constant rate in a suitable amount according to conditions of the critical patient.
If the suitable amount of the special liquid medicine for injection is not continuously administered at a constant rate to the patient, there is a high possibility of side reactions, such as anaphylactic shock.
Thus, it is necessary to provide an injection volume regulating device for a liquid medicine, which enables continuous injection of the liquid medicine at a constant rate into the blood vessel.
The conventional clamp can regulate the injection volume of the liquid medicine such that about 70˜80 /hr of liquid medicine is delivered therethrough. The conventional clamp is equipped to an outer portion of a hose which is hermetically connected to a lower end of a pack containing a liquid medicine and to a needle, and regulates the injection volume of the liquid medicine through change in cross-sectional area of the hose by compressing the hose.
Generally, the hose is compressed by a regulating member, which can move up and down along a tapered guider, and which comprises a roller typically having small teeth formed on an outer surface thereof. The guider is tapered such that, when the roller reaches one end of the guider, the roller compresses the hose, and when the roller reaches the other end, it completely opens the hose.
With this construction, the injection volume of the liquid medicine flowing in the needle is regulated by changing the cross-sectional area of the hose while rolling the regulating member up and down along the guider. However, with the conventional clamp, it is very difficult to accurately adjust a flux of the liquid medicine since the regulating member cannot tightly compress the hose when it is excessively used, and since the hose is composed of a synthetic resin or a rubber material.
Accordingly, during administration of the liquid medicine using the conventional clamp, changes in administration amount of the liquid medicine occur due to deformation of the regulating member as described above, requiring a nurse to frequently confirm the administration amount of the liquid medicine.
However, since the conventional clamp has advantages of a lower price and a simple construction, it is often used for the case where the liquid medicine is administered to a patient for a short period of time without high accuracy.
Although an infusion pump is known in the art as a device for precise regulation in infusion amount of a liquid medicine, the infusion pump is very expensive, resulting in heavy cost burdens to employ infusion pumps. In addition, a rechargeable electric device usually contained in the infusion pump may cause defective operation of the infusion pump, and large volume and heaviness of the infusion pump hinders portability.
However, it is necessary to use a device for precise regulation in pediatrics.
A flow controller is a disposable device for precisely regulating the injection volume of the liquid medicine, and can be used for the infant patient, an elderly patient, a patient suffering from adverse drug reaction, a patient requiring anti-cancer injection, and the like. The flow controller is inexpensive, and can replace the clamp and the infusion pump.
The flow controller ensures continuous administration of the liquid medicine at a constant rate for 24 hours or more after being set once, and is inexpensive in comparison to the infusion pump. The flow controller is highly portable, provides user convenience, and is applicable to all patients requiring injection. In addition, the flow controller reduces nurse workload and provides stability.
Various types of flow controller as described above have been developed, and generally have a spiral or arcuate shape.
However, the conventional flow controller has passages defining a plane perpendicular to an injecting direction of the liquid medicine, and two flat disks facing each other while being parallelly located at upper and lower portions, and an inlet and an outlet formed at the center of the disks, respectively.
As a result, it is difficult to manufacture the conventional flow controller and to operate the flow controller with one hand due to the complicate structure, such as two or more passages formed therein, increasing manufacturing costs.
In order to solve this problem, the applicant of the present invention invented a device, entitled Injection volume regulating device for liquid medicine, and filed it with Korean Industrial Property Office on Nov. 29, 2001 (Korean Patent Application No. 10-2001-0074845). The device comprises a regulating member, a fixing member, a rubber packing, and a fastening member. The invention of the disclosure is characterized in that the device has a single passage which is formed in a plane parallel to the injecting direction of the liquid medicine. The device comprises two flat disks, i.e. the fixing member and the regulating member, facing each other while being parallelly located at the right and left sides, and an inlet and an outlet formed at upper and lower portions of the fixing member.
The passage is formed in the device such that the liquid medicine enters the inlet of the fixing member, and passes through the passage formed in the regulating member, and is then discharged through the outlet of the fixing member. The passage has an arcuate shape with its central angle being about 350 degrees, and has a tapered cross-section.
However, the device of the disclosure has problems in that the rubber packing compresses the passage and interferes with flow of the liquid medicine, the fastening member is pushed by restoring force of the rubber packing, and in that the rubber packing is not fixed in the device.
Additionally, although it is needed to provide an injection volume regulating device for a liquid medicine which can be easily adjustable with one hand for enhancing operating efficiency of a user, a device completely solving the above described problems has yet to be developed.